This invention relates to nozzles for controlling gas flow and, more particularly, for controlling said gas flow in a laser.
Mass flow rates of gases generally, and in a laser in particular, can be controlled by use of the phenomenon known to those of ordinary skill in the art as "sonic choking". To make use of this phenomenon in a gas flow laser, a single two-layered gas flow control plate is employed. Numerous small holes are drilled through the plate, with each drilled hole being used as a two-piece gas flow control nozzle. For use in a high energy gas laser, a great many of these very small drilled holes are required in the gas flow control plate to ensure homogineity of the gas in order to produce an acceptable beam path. For example, one such flow plate with dimensions of 108.5.times.9.25.times.0.782 inches which is used in a particular high energy gas laser contains 123,173 of the very small holes (i.e., nozzles), with each having a throat measuring 0.0225 of an inch in diameter. In addition, it is to be noted and remembered that for laser applications, high voltages are encountered which require the flow plate to be constructed of a dielectric material, such as fiberglass.
The cost of drilling the aforesaid numerous holes in the fiberglass flow plate is very high. In addition, the rapid erosion of the fiberglass holes requires the premature replacement of the entire flow plate, with accompanying lost time and added cost for replacement. Further, the internal roughness of the holes because of the frayed ends of the fiber glass, which cannot be either controlled or predicted, prevents adequate analytical analysis of the gas flow.